Tandy TRS-80 Owner Manual & Programming Manual page 47

A MORE
OIRECT
APPROACH
90
INPUT "TYPE NEW NAME ELSE PRESS
<ENTER>"; At
90 if
fi*
=
""
THEN 20
100
WRITE
»1
,
A*
110 PUT *1
t
R
120 GOTO 20
130
CLOSE
*1
RUN
it.
See
how
all
your
records
initially
contain
"NO NAME."
Then, you can change
the
data
in
any
of the records at will, as
many
times
as
you
want.
(To
end
the
program,
type
a
as the
RECORD
NO.)
READING ALL THE RECORDS
At
this point,
you might
like
the
Computer
to
print
all
of the records in
your
"NAMES/DAT"
file
with
their appropriate record
numbers.
SAVE
your program,
if
you want,
erase
memory,
type,
and
RUN:
10
OPEN
"D"
,
*1
»
"NAMES/DAT"
20
R =
1
32
GET
*1
.
R
40
INPUT «1
t
At
50
PRINT At
"
60 IF
R = 10
THEN 90
70
R = R
+
1
80
GOTO
30
90
CLOSE *1
13 IN
RECORD"
R
Line 20
makes
R
equal
to
1.
In the
next
lines,
the
Computer GETs, INPUTs, and
PRINTs
record
1.
Line 70 then
makes
R
equal
to
2
and
the
whole
process
is
repeated with record
2.
When R
equals
10
—
the
last
record
in
the
file
—
the
program
ends.
There
are
many
occasions
when
you
will
not
know
the
last
record
number
in
the
file.
Change
line
60
and
RUN
the program:
G0
IF R
L0F(
1
)
THEN
90
LOF
looks
at
the
file
which
buffer
#1
(the
number
in parenthesis)
is
communicating
with.
It tells
the
Computer what
the
last
record
number
in that
file is.
MORE POWER
TO
A RECORD
So
far,
we
have been
PUTting
only
one
"field"
of
data
in
each
record.
We
can
make
the
file
more
organized
by
subdividing each record
into several
fields.
Erase memory,
type,
and
RUN
this
program:
*1
.
"BUG9/DAT"
"FLIE9"
t
1000000* "HAIRY"
10
OPEN
"D"
20 WRITE
*1
30 PUT
»1
.
2
34 GET #1
.
2
35 INPUT
*i
.
D*. N. T$
38 PRINT Dt
,
Nt Tt
W
CLOSE
#1
Line 20
WRITEs
three
fields
of data into buffer
#1.
Then,
line
30
PUTs
the entire contents
of
buffer
#1
(all
three
fields)
into
record 2 of the
file:
*BU&S/ DfilT
"
record
1
"FLIES
t
I
000000
»
"HAIRY"
record
2
/
Line 34
GETs
everything
in record 2
and
reads
it
into buffer #1.
Then,
line
36
INPUTs
all
three
fields
of
data from
buffer
#1
and
labels
them
as
D$, N, and
T$.
Try
substituting
this for line
36
and
RUN
. .
38
INPUT
*1
i
Dt
Since
this line
asks the
Computer
to
INPUT
only
the
first field
of
data
in buffer #1,
it
INPUTs
only
"FLIES."
37